A classic rave/club-whore term that refers to a brief (30-90 minute) nap which a person takes in between two large events (e.g., raves and circuit parties). Because both events may span hours into the double-digits, there is little time to sleep. A disco nap helps to afford one the energy to make it through the second event.

A nap that you take before you go out to the bar/dancing so that you'll be more awake and have the energy to party more!

friend 1: "Hey what time should we meet... 7:00?"
friend 2: "No, better make it 8:00... I need to take a disconap first."
OR
friend 1: "Hey, it's getting late; do you want to leave soon?"
friend 2: "Hells no! I took a disconap earlier, so I'm good to go!"